Thua thay, bai toan co the duoc giai quyet bang phuong phap nhan
tu Lagragne va co dap so la min(x+y+z)=15/2 <=> (x, y, z)=(3,
5/2, 2). Tuy nhien, mot nguoi giai duoc mot bai toan hay chua han
la da chinh phuc duoc 100% ve dep bai toan ma chi co 49& thoi,
51% con lai thuoc ve nguoi sang tao ra bai toan do. Nhu thay da
gioi thieu tai seminar ngay 21/06 vua qua thi cac hang so 2, 4, 7
xuat tu 1 pt bac 3 cua bai toan tong quat sau: Cho a, b, c, x, y,
z > 0 thoa ax+by+cz=xyz, tim min S=x+y+z. Va cung dua vao pp nhan
tu Lagrange, chung ta cung co the chung minh duoc 1 ket qua kha
chat che, nhung dau bang chua xay ra, do la x+y+z >
sqrt(4(a+b+c)+sqrt(8(ab+bc+ca))).
PS: Thua thay,em van khong the nao xep nhieu hon 21 chiec xe va
bai co 36 o nhu thay da noi tai seminar, em mong duoc thay chi
giao, cam on thay.